Some MOS transistors have an active portion comprising a semiconductor fin laid on a support, an insulated conductive gate located on two or three sides of the fin enabling, according to the biasing state of the transistor, to set it to an on or off state. Such a transistor is sometimes called finFET (“fin Field Effect Transistor”) in the art. In the present disclosure, transistors of this type are called fin transistors.
It has especially been provided to form a fin transistor based on an SOI-type (“semiconductor on insulator”) structure comprising a semiconductor layer on a silicon oxide layer coating a semiconductor support. The fin is then formed in the semiconductor layer of the SOI structure.
In practice, the manufacturing of fin MOS transistors on an SOI structure raises technical issues.